Slow random write IOPS with samsung 840 pro 128gb / help??

i recently put together a new machine :

Asrock extreme 4 z77
intel i7 - 3770k
8gb corsair vengeance 1600mhz
samsung 840 pro 128 gb

I am not getting anywhere near the 90000 IOPS that samsung has advertised, im getting about half of that around 40-45k iops on my random write speeds. All other speeds sequentials r/w and random read are all right at advertised speeds. Whats wierd is ive only gotten the advertised 90000 IOPS random read speed one time, so i dont know if it was a fluke or something.

All of my ports are correct, im connected to the intel controller sata 3 6gb link, ive made sure through my motherboard. Im also on the newest samsung firmware

I have everything set to AHCI mode in bios and SSD mode.

Here is a screenshot with a recent benchmark using AS SSD





Ive noticed that people's latency is also lower than mine using the same drive. Ive also included a compression benchmark...which if you look at the lines, they seem a bit too jittery. Anandtech's review had the graph at a straight line while mine look like jagged edges:




Ive updated all intel rapid storage technology drivers, all intel chipset drivers, even the Asmedia sata 2 controller drivers.

Is there maybe a certain something that is causing my random read to be low? Ive hit the 90k mark before, what could have happened? What could be causing my drive to be higher latency?

Did you try to play around with CPU power saving options? AHCI is relatively dumb and relies on CPU interaction for high IOPS. Even running Prime95 while running a benchmark will reduce response times as it keeps the CPU from entering deep power saving states.

omniscence said:

Did you try to play around with CPU power saving options? AHCI is relatively dumb and relies on CPU interaction for high IOPS. Even running Prime95 while running a benchmark will reduce response times as it keeps the CPU from entering deep power saving states.

Click to expand...

im going to guess you are referring to the c...something states in the bios? ive never messed with any of that stuff before so im not sure what i should turn off or on. Can you suggest what i do in bios or what i should look for?

or is this done through software through control panel > power options?

You can increase your speeds by not running the benchmark on your OS drive, and also by running one thread of Prime95 in the background (or disabling all Cx states in the BIOS). However, I doubt you can get 90K write IOPS with a 128GB drive (that spec is for the 256 and higher GB models). I have hit 75K write IOPS on a 128GB Samsung 840 Pro.